Gamevar operators: Difference between revisions
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Helixhorned (talk | contribs) add some general info; and to div and mod. Make % sign undefined, see http://en.wikipedia.org/wiki/Modulo_operation C89 vs. C99. |
Hendricks266 (talk | contribs) No edit summary |
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For example: | For example: | ||
setvar temp | setvar temp 1 // assigns a value of 1 to the gamevar ''temp''. | ||
addvar temp 1 // adds 1 to ''temp'', causing its value to become 2. | addvar temp 1 // adds 1 to ''temp'', causing its value to become 2. | ||
Line 41: | Line 41: | ||
|<code>/</code> | |<code>/</code> | ||
|÷ | |÷ | ||
|division with rounding toward 0 | |division with rounding toward 0 for nonnegative dividends | ||
|Ensure that <value> does not equal 0 at any time. | |Ensure that <value> does not equal 0 at any time. '''The rounding behavior is undefined for negative dividends.''' | ||
|- | |- | ||
|mod | |mod | ||
Line 48: | Line 48: | ||
| | | | ||
|[[Wikipedia:Modulo operation|modulo]], remainder | |[[Wikipedia:Modulo operation|modulo]], remainder | ||
|Ensure that <value> does not equal 0 at any time; | |Ensure that <value> does not equal 0 at any time; sign of the result is that of left hand side operand (dividend). | ||
|- | |- | ||
|and | |and | ||
|<code>&</code> | |<code>&</code> | ||
| | | | ||
|bitwise AND | |[[Wikipedia:Bitwise operation|bitwise]] AND | ||
|The bits in the result are set only if they were set in both of the values being operated on. | |The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system|base-2]]): 01001010 AND 11110100 is 01000000 | ||
|- | |- | ||
|or | |or | ||
|<code><nowiki>|</nowiki></code> | |<code><nowiki>|</nowiki></code> | ||
| | | | ||
|bitwise OR | |[[Wikipedia:Bitwise operation|bitwise]] OR | ||
|The bits in the result are set only if they were set in either of the values being operated on. | |The bits in the result are set only if they were set in either of the values being operated on. Ex.: 01001010 OR 11110100 is 11111110 | ||
|- | |- | ||
|xor | |xor | ||
|<code>^</code> | |<code>^</code> | ||
| | | | ||
|bitwise XOR | |[[Wikipedia:Bitwise operation|bitwise]] XOR | ||
|The bits in the result are set if only one of the values being operated on has those bits set. | |The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110 | ||
|} | |} | ||
Revision as of 13:21, 8 March 2015
<operator>var <gamevar> <value>
<operator>varvar <gamevar> <value>
Gamevar operators are commands that perform various mathematical and bitwise logical operations on gamevars. The first argument must be a writable gamevar and is taken as the destination as well and the first operand (2-address code).
For example:
setvar temp 1 // assigns a value of 1 to the gamevar temp. addvar temp 1 // adds 1 to temp, causing its value to become 2. mulvar temp 2 // multiplies temp by 2, causing its value to become 4.
Operator | C/C++ | Math | Description | Notes | |
---|---|---|---|---|---|
set | =
|
= | assignment | ||
add | +
|
+ | addition | ||
sub | -
|
– | subtraction | ||
mul | *
|
× | multiplication | ||
div | /
|
÷ | division with rounding toward 0 for nonnegative dividends | Ensure that <value> does not equal 0 at any time. The rounding behavior is undefined for negative dividends. | |
mod | %
|
modulo, remainder | Ensure that <value> does not equal 0 at any time; sign of the result is that of left hand side operand (dividend). | ||
and | &
|
bitwise AND | The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are base-2): 01001010 AND 11110100 is 01000000 | ||
or | |
|
bitwise OR | The bits in the result are set only if they were set in either of the values being operated on. Ex.: 01001010 OR 11110100 is 11111110 | ||
xor | ^
|
bitwise XOR | The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110 |
Commands with an additional "var" suffix take gamevars rather than constants or defined labels for their inputs. As an alternate short form, "varvar" can be dropped from these commands; for example ife serves an an alias for ifvarvare.